Microsphere articles and transfer articles

ABSTRACT

There is provided an article comprising at least a first surface having: (a) a first binder layer; (b) a plurality of transparent microspheres at least partially embedded in the first binder layer; wherein the transparent microspheres have refractive indices that are less than a refractive index of the first binder layer, wherein the plurality of transparent microspheres have an average diameter of at least 5 μm. There is also provided a transfer article comprising: (a) a transfer carrier, the transfer carrier comprising: (i) a support layer; and (ii) a thermoplastic release layer bonded to the support layer; (b) a layer of a plurality of transparent microspheres, formed on a side of the thermoplastic transparent microsphere release layer opposite the support layer, wherein the plurality of transparent microspheres have refractive indices of below about 1.490.

FIELD

This disclosure relates to articles and transfer articles that arecoated with transparent microspheres.

BACKGROUND

Decorative protective surfaces find many consumer applications.Household appliances, automotive interiors and paints, consumerelectronic devices, such as laptops and hand held devices, are allexamples where consumers prefer materials that deliver considerableprotection from scratches, wear and abrasion while retaining highcosmetics and aesthetics throughout the material's lifecycle. Low glossmatte surfaces are of particular interest to many consumers because oftheir aesthetic appeal.

Durable decorative laminates and films comprised of glass beads arebroadly known. These low gloss constructions typically consist ofexposed glass bead surfaces that impart high durability and decorativeproperties to the construction. Low friction properties of suchconstructions have also been disclosed. For example, U.S. Pat. No.4,849,265 (Ueda) discloses decorative abrasion resistant laminates thatcontain hard microspheres (glass or plastic) that are either exposed orsurface coated with a thin polymer coating. There is no disclosure aboutthe influence of refractive index of the microspheres on the true colorof the final laminate.

Known methods for providing true color in decorative materials includeclosely matching the refractive index of the individual components, soas to minimize reflections due to index mismatch. For example, U.S. Pat.No. 5,620,775 (LaPerre) discloses decorative articles comprising exposedglass bead surfaces. The disclosed construction has the appearance of anetched surface and a rainbow like optical appearance. There is nodisclosure about adjusting the refractive index to get a more true colorin the final article.

It is known that it is advantageous to select microspheres having arefractive index in a range that is close to that of commonly usedpolymer films in order to provide true color of the underlying pigmentedpolymer. For example, U.S. Pat. No. 5,620,775 (LaPerre) disclosesdurable, low coefficient of friction polymeric films made by having anexposed glass bead surface with glass beads having a refractive index inthe range of about 1.5 to about 1.6, which is a refractive index rangeclose to that of common polymers.

There is a need for microsphere coated articles and transfer articlesthat provide improvements in aesthetics, such as true color, whilemaintaining abrasion and wear resistance provided by conventionalmicrosphere coated articles and transfer articles.

SUMMARY

The present disclosure provides low gloss polymeric films containingpartially exposed transparent microspheres with improved aesthetics anda true color appearance. It has been surprisingly found that in the caseof a transparent microsphere multilayer film, by increasing the mismatchin refractive index between a plurality of transparent microspheres anda binder layer, the color of the underlying layers, such as the binderlayer and other substrates, is brought out better. It has beensurprisingly observed that, particularly in the case of dark colorpigmented articles, the true color of the underlying binder layer and/orother substrates is improved when selecting a plurality of transparentmicrospheres having a lower refractive index than that of the binderlayer. In some embodiments, it has been surprisingly found that the truecolor of the underlying binder layer and/or other substrates is improvedwhen selecting a plurality of transparent microspheres having arefractive index of less than about 1.490.

In one aspect, the present disclosure provides an article comprising atleast a first surface having: (a) a first binder layer; (b) a pluralityof transparent microspheres at least partially embedded in the firstbinder layer; wherein the transparent microspheres have refractiveindices that are less than a refractive index of the first binder layer,wherein the plurality of transparent microspheres have an averagediameter of at least 5 μm. In some embodiments, the plurality oftransparent microspheres has a refractive index of less than 1.490. Insome embodiments, the plurality of transparent microspheres are selectedfrom at least one of glass, polymers, glass ceramics and ceramics. Insome embodiments, the first binder layer is selected from at least oneof polyurethanes, polyesters, acrylic and methacrylic acid esterpolymers and copolymers, epoxies, polyvinyl chloride polymers andcopolymers, polyvinyl acetate polymers and copolymers, polyamidepolymers and copolymers, fluorine containing polymers and copolymers,silicones, silicone containing copolymers, elastomers, includingsynthetic and natural rubbers such as neoprene, acrylonitrile butadienecopolymers, metals, glass, ceramics, polymer matrix composites, andcombinations thereof. In some embodiments, the first binder layer is anadhesive.

In some embodiments, the plurality of transparent microspheres have anaverage diameter of no greater than 200 μm. In some embodiments, up toabout 91% of the surface of the article is covered with the plurality oftransparent microspheres. In some embodiments, at least one of thearticle or the binder layer comprises a pigment. In some embodiments,the plurality of transparent microspheres are partially embedded in thefirst binder layer such that about 20% to about 70% of the averagediameter of the transparent microspheres is exposed.

In some embodiments, the plurality of transparent microspheres have amulti-modal size distribution. In some embodiments, the article is atleast one of a decorative film, a protective film, a transfer article.In some embodiments, the article further comprises one or more layersselected from the group consisting of substrate layers, adhesive layers,colored polymeric layers, and release layers bonded to the article on aside of the first binder layer opposite the plurality of transparentmicrospheres, wherein any of said layers can optionally have a graphicdesign therein. In some embodiments, the substrate layer may be from atleast one of fabrics, polymer coated fabrics, leather, metal, paintcoated metal, elastomers, paper, polymer matrix composites, andpolymeric materials. In some embodiments, the transparent microspheresare treated with an adhesion promoter. In some embodiments, the firstbinder layer is transparent.

In another aspect, the present disclosure provides a transfer articlecomprising: (a) a transfer carrier, the transfer carrier comprising: (i)a support layer; and (ii) a thermoplastic release layer bonded to thesupport layer; (b) a layer of a plurality of transparent microspheres,formed on a side of the thermoplastic transparent microsphere releaselayer opposite the support layer, wherein the plurality of transparentmicrospheres have refractive indices of below about 1.490. In someembodiments, the transfer articles further comprises (c) a binder layeron a side of the plurality of transparent microspheres that is oppositethe thermoplastic release layer.

In some embodiments, the plurality of transparent microspheres areselected from at least one of glass, polymers, glass ceramics andceramics.

In some embodiments, the first binder layer is selected from at leastone of polyurethanes, polyesters, acrylic and methacrylic acid esterpolymers and copolymers, epoxies, polyvinyl chloride polymers andcopolymers, polyvinyl acetate polymers and copolymers, polyamidepolymers and copolymers, fluorine containing polymers and copolymers,silicones, silicone containing copolymers, elastomers, includingsynthetic and natural rubbers such as neoprene, acrylonitrile butadienecopolymers, metals, glass, ceramics, polymer matrix composites, andcombinations thereof. In some embodiments, the first binder layer is anadhesive.

In some embodiments, the plurality of transparent microspheres have anaverage diameter of no greater than 200 μm. In some embodiments, up toabout 91% of the surface of the article is covered with the plurality oftransparent microspheres. In some embodiments, at least one of thetransfer article or the binder layer comprises a pigment. In someembodiments, the microsphere article further comprises a colored layeropposite the surface comprising the embedded microspheres. In oneembodiment, the colored layer is a graphic print applied to the backsideof the microsphere article.

In some embodiments, the plurality of transparent microspheres arepartially embedded in the first binder layer such that about 20% toabout 70% of the average diameter of the transparent microspheres isexposed. In some embodiments, the plurality of transparent microsphereshas a multi-modal size distribution. In some embodiments, the transferarticle further comprises at least one layer selected from at least oneof substrate layers, adhesive layers, colored polymeric layers, andrelease layers bonded to the article on a side of the first binder layeropposite the plurality of transparent microspheres, wherein any of saidlayers can optionally have a graphic design therein.

In some embodiments, the substrate layer from at least one of fabrics,polymer coated fabrics, leather, metal, paint coated metal, elastomers,paper, polymer matrix composites, and polymeric materials. In someembodiments, the transparent microspheres are treated with an adhesionpromoter. In some embodiments, the first binder layer is discontinuousand wherein the binder layer is capable of bonding to a substrate layer.

The above summary of the present disclosure is not intended to describeeach embodiment of the present invention. The details of one or moreembodiments of the invention are also set forth in the descriptionbelow. Other features, objects, and advantages of the invention will beapparent from the description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section one embodiment of an article of the presentdisclosure; and

FIG. 2 is a cross-section of one embodiment of a transfer article of thepresent disclosure.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description. The invention is capable of otherembodiments and of being practiced or of being carried out in variousways. Also, it is to be understood that the phraseology and terminologyused herein is for the purpose of description and should not be regardedas limiting. The use of “including,” “comprising,” or “having” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Anynumerical range recited herein includes all values from the lower valueto the upper value. For example, if a concentration range is stated as1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, or1% to 3%, etc., are expressly enumerated. These are only examples ofwhat is specifically intended, and all possible combinations ofnumerical values between and including the lowest value and the highestvalue enumerated are to be considered to be expressly stated in thisapplication.

Transfer Carrier

The transfer coating method of the present disclosure can be used toform the presently disclosed microsphere transfer article from which canbe formed the presently disclosed microsphere article. The microspherearticle has surprisingly improved aesthetics.

The presently disclosed transfer carrier includes a support layer and athermoplastic release layer bonded thereto. The thermoplastic releaselayer of the transfer carrier temporarily partially embeds a pluralityof transparent microspheres. In one embodiment, the plurality oftransparent microspheres are embedded about at least 5%, 10%, 20%, 30%,40%, or even 50%, and no more than 60%, 70% or even 80% of thetransparent microsphere diameter into the thermoplastic release layer.The transfer carrier has low adhesion to the plurality of transparentmicrospheres and to the binder layer in which the opposite sides of theplurality of transparent microspheres are at least partially embedded,so that the transfer carrier can be removed to expose the surface of theplurality of transparent microspheres.

Because the microsphere articles of the present disclosure areconstructed wherein at one point the transparent microspheres areembedded in both a thermoplastic release layer and a binder layer, whenthe thermoplastic release layer is removed, the transparent microspheresare partially embedded in the binder layer. This means that theplurality of transparent microspheres are embedded about at least 20%,30%, or even 40% and at most 60%, 70%, 80%, 90%, or even 95% of thetransparent microsphere diameter into the binder layer.

Support Layer

The support layer should be “dimensionally stable”. In other words itshould not shrink, expand, phase change, etc. during the preparation ofthe transfer article. Useful support layers may be thermoplastic,non-thermoplastic or thermosetting, for example. One skilled in the artwould be able to select a useful support layer for the presentlydisclosed transfer article. If the support layer is a thermoplasticlayer it should preferably have a melting point above that of thethermoplastic release layer of the transfer carrier. Useful supportlayers for forming the transfer carrier include but are not limited tothose selected from at least one of paper and polymeric films such asbiaxially oriented polyethylene terephthalate (PET), polypropylene,polymethylpentene and the like which exhibit good temperature stabilityand tensile so they can undergo processing operations such as beadcoating, adhesive coating, drying, printing, and the like.

Thermoplastic Release Layers

Useful thermoplastic release layers for forming the transfer carrierinclude but are not limited to those selected from at least one ofpolyolefins such as polyethylene, polypropylene, organic waxes, blendsthereof, and the like. Low to medium density (about 0.910 to 0.940 g/ccdensity) polyethylene is preferred because it has a melting point highenough to accommodate subsequent coating and drying operations which maybe involved in preparing the transfer article, and also because itreleases from a range of adhesive materials which may be used as thebinder layer, in addition to the plurality of transparent microspheres.

The thickness of the thermoplastic release layer is chosen according tothe microsphere diameter distribution to be coated. The binder layerembedment becomes approximately the mirror image of the transfer carrierembedment. For example, a transparent microsphere which is embedded toabout 30% of its diameter in the release layer of the transfer carrieris typically embedded to about 70% of its diameter in the binder layer.To maximize slipperiness and packing density of the plurality ofmicrospheres, it is desirable to control the embedment process so thatthe upper surface of smaller microspheres and larger microspheres in agiven population of the exposed microspheres are approximately the sameheight after the transfer carrier is removed.

In order to partially embed the plurality of transparent microspheres inthe release layer, the release layer should preferably be in a tackystate (either inherently tacky and/or by heating). The plurality oftransparent microspheres may be partially embedded, for example, bycoating a plurality of transparent microspheres on the thermoplasticrelease layer of the transfer carrier followed by one of (1)-(3):(1)heating the microsphere coated transfer carrier, (2) applying pressureto the microsphere coated transfer carrier (with, for example, a roller)or (3) heating and applying pressure to the microsphere coated transfercarrier.

For a given thermoplastic release layer, the microsphere embedmentprocess is controlled primarily by temperature, time of heating andthickness of the thermoplastic release layer. As the thermoplasticrelease layer is melted, the smaller microspheres in any givenpopulation will embed at a faster rate and to a greater extent than thelarger microspheres because of surface wetting forces. The interface ofthe thermoplastic release layer with the support layer becomes anembedment bounding surface since the microspheres will sink until theyare stopped by the dimensionally stable support layer. For this reasonit is preferable that this interface be relatively flat.

The thickness of the thermoplastic release layer should be chosen toprevent encapsulation of most of the smaller diameter microspheres sothat they will not be pulled away from the binder layer when thetransfer carrier is removed. On the other hand, the thermoplasticrelease layer must be thick enough so that the larger microspheres inthe plurality of transparent microspheres are sufficiently embedded toprevent their loss during subsequent processing operations (such ascoating with the binder layer, for example). In one embodiment, thethickness of the thermoplastic release layer is at least 2.5 microns, 10microns, 25 microns, or even 50 microns. In one embodiment, thethickness of the thermoplastic release layer is at most 75 microns, 100microns, or even 150 microns.

Low Refractive Index Transparent Microspheres

The terms “transparent microspheres” and “microspheres” are usedinterchangeably herein.

The transparent microspheres useful in the present disclosure can bemade using any material having a refractive index lower than thematerial used in the binder layer. In some embodiments, the transparentmicrospheres have a refractive index of no more than about 1.490. Insome embodiments, the transparent microspheres have a refractive indexof no more than about 1.480. In some embodiments, the transparentmicrospheres have a refractive index of no more than about 1.470. Insome embodiments, the transparent microspheres have a refractive indexof no more than about 1.460. In some embodiments, the transparentmicrospheres have a refractive index of no more than about 1.450. Insome embodiments, the transparent microspheres have a refractive indexof no more than about 1.400. Typically, the transparent microsphereshave a refractive index of more than 1.00.

In some embodiments, the transparent microspheres are glass beads. Theglass beads are largely spherically shaped. The glass beads aretypically made by from ordinary soda-lime glass or borosilicate glass,typically from recycled sources such as from glassware. Commonindustrial glasses could be of varying refractive indices depending ontheir composition. Soda lime silicates and borosilicates are some of thecommon types of glasses. Borosilicate glasses typically contain boriaand silica along with other elemental oxides such as alkali metaloxides, alumina etc. Some glasses used in the industry that containboria and silica among other oxides include E glass which has arefractive index close to 1.57; glass available under the tradedesignation “NEXTERION GLASS D” from Schott Industries, Kansas City,Mo., which has a refractive index of 1.52; and glass available under thetrade designation “PYREX” from Corning Incorporated, New York, N.Y.,which has a refractive index around 1.47. In one embodiment, thetransparent microspheres comprise at least 5%, 10%, or even 12% boronoxide by weight.

The grinding process yields a wide distribution of glass particle sizes.The glass particles are spherodized by treating in a heated column tomelt the glass into spherical droplets, which are subsequently cooled.Not all the beads are perfect spheres. Some are oblate, some are meltedtogether and some contain small bubbles.

Microspheres are preferably free of defects. As used herein, the phrase“free of defects” means that the microspheres have low amounts of bubbletype defects, low amounts of irregular shaped particles, low amount ofinhomogenieties, or low amounts undesirable of color or tint. Typically,materials that have at least 70% (by count) defect free microspheres maybe preferred. In some embodiments of the present disclosure, materialsthat have at least 75%, 80%, 85%, 90% or even 99% defect freemicrospheres may be preferred. Materials that have less than 75% defectfree microspheres are not desirable for aesthetic purposes.

Particle Sizing

The transparent microspheres are typically sized via screen sieves toprovide a useful distribution of particle sizes. Sieving is also used tocharacterize the size of the transparent microspheres. With sieving, aseries of screens with controlled sized openings is used and themicrospheres passing through the openings are assumed to be equal to orsmaller than that opening size. For microspheres, this is true becausethe cross-sectional diameter of the microsphere is almost always thesame no matter how it is oriented to a screen opening. It is desirableto use as broad a size range as possible to control economics andmaximize the packing of the microspheres on the binder layer surface.However, some applications may require limiting the microsphere sizerange to provide a more uniform microsphere coated surface. In someembodiments, a useful range of average microsphere diameters is about 5μm to about 200 μm (typically about 35 to about 140 μm, preferably about35 to 90 μm, and most preferably about 38 to about 75 μm). A smallnumber (0 to 5% by weight based on the total number of microspheres) ofsmaller and larger microspheres falling outside the 20 to 180 micronrange can be tolerated. In some embodiments, a multi-modal sizedistribution of microspheres is useful. For example, in a bi-modaldistribution two distinct peaks in the population density of themicrospheres are observed.

In some embodiments, to calculate the “average diameter” of a mixture ofmicrospheres one would sieve a given weight of particles such as, forexample, a 100 gram sample through a stack of standard sieves. Theuppermost sieve would have the largest rated opening and the lowestsieve would have the smallest rated opening. For our purpose, theaverage cross-sectional diameter can be effectively measure by using thefollowing stack of sieves.

U.S. Sieve Designation No. Nominal Opening (microns).  80 180  100 150 120 125  140 106 170 90 200 75 230 63 270 53 325 45 400 38 500 25 63520

Alternately, average diameter can be determined using any commonly knownmicroscopic methods for sizing particles. For example, opticalmicroscopy or scanning electron microscropy, and the like, can be usedin combination with any image analysis software. For example, softwarecommercially available as free ware under the trade designation “IMAGEJ” from NIH, Bethesda, Md.

Adhesion Promoter

In some embodiments, the transparent microspheres are treated with anadhesion promoter such as those selected from at least one of silanecoupling agents, titanates, zirconates, organo-chromium complexes, andthe like, to maximize their adhesion to the binder layer, especiallywith regard to moisture resistance.

The treatment level for such adhesion promoters is on the order of 50 to1200 parts by weight adhesion promoter per million parts by weightmicrospheres. Microspheres having smaller diameters would typically betreated at higher levels because of their higher surface area. Treatmentis typically accomplished by spray drying or wet mixing a dilutesolution such as an alcohol solution (such as ethyl or isopropylalcohol, for example) of the adhesion promoter with the microspheres,followed by drying in a tumbler or auger-fed dryer to prevent themicrospheres from sticking together. One skilled in the art would beable to determine how to best treat the microspheres with an adhesionpromoter.

Binder Layer

The binder layer (also referred to as the “first binder layer”) istypically an organic polymeric material. It should exhibit good adhesionto the transparent microspheres themselves or to the treatedmicrospheres. It is also possible that an adhesion promoter for thetransparent microspheres could be added directly to the binder layeritself as long as it is compatible within the process window fordisposing the binder layer on the surfaces of the transparentmicrospheres. It is important that the binder layer has sufficientrelease from the thermoplastic release layer of the transfer carrier toallow removal of the transfer carrier from the transparent microspheres,which are embedded on one side in the thermoplastic release layer and onthe other side in the binder layer.

Binders useful in the binder layer include, but are not limited to thoseselected from at least one of polyurethanes, polyesters, acrylic andmethacrylic acid ester polymers and copolymers, epoxies, polyvinylchloride polymers and copolymers, polyvinyl acetate polymers andcopolymers, polyamide polymers and copolymers, fluorine containingpolymers and copolymers, silicones, silicone containing copolymers,elastomers, including synthetic and natural rubbers such as neoprene,acrylonitrile butadiene copolymers, metals, glass, ceramics, polymermatrix composites, and combinations thereof. In some embodiments, thepolymer matrix composites include nanoparticles in resins, fibers inresins, and the like.

Combinations can include any combinations of materials, such asinterpenetrating networks, dual cure systems, and the like.

In some embodiments, the refractive index of the binder is greater than1.50, 1.52, 1.55, or even 1.6. In some embodiments, the refractive indexof the binder layer is no more than 1.35, 1.38, 1.40 or even 1.45.

The binder layer can be formed, for example, out of solution, aqueousdispersion, or 100% solids coating such as via hot melt or extrusion.The binder layer may be transparent, translucent, or opaque. It may becolored or colorless. The binder layer may, for example, be clear andcolorless or pigmented with opaque, transparent, or translucent dyesand/or pigments. In some embodiments, inclusion of specialty pigments,such as for example metallic flake pigments, can be useful.

In one embodiment, the thickness of the binder layer is at least 50% ofthe average diameter of the transparent microspheres. For example, 10,25, 50, 100, or even 250 μm (micrometers) or even more (e.g., at least 1millimeter, at least 1 centimeter, or even 1 meter).

If retroreflective performance is desired in at least a portion of thesurface layer of the presently disclosed microsphere coated article,such that a reflecting layer (such as a thin metallic layer such as analuminum flake ink layer, for example) is coated on the buried(non-exposed) side of the transparent microspheres, it is preferred thatthe binder layer be transparent and thin such that it maintains thecontours of the transparent microspheres, so that it can also functionas a spacing layer to focus the incident light on the reflecting layerplaced below it.

The binder layer is typically formed on the transfer carrier after thetransparent microspheres have been partially embedded in the releaselayer of the transfer carrier. The binder layer is typically coated overthe partially embedded transparent microspheres by a direct coatingprocess but could also be provided over the transparent microspheres viathermal lamination either from a separate carrier or by first formingthe binder layer on a separate substrate from which it is subsequentlytransferred to cover the transparent microspheres.

In one embodiment, the present disclosure enables a more true color ofthe article. In other words, the constructions of the present disclosureenable a minimizing the perceived brightness/lightness of the articlewhen viewed through the transparent microspheres.

In the CIELAB color space, L* is the measure of lightness or brightnessof a colored surface (for example L* of pure black is typically 0 and L*of diffuse white is 100). Although not wanting to be limited by theory,it is believed that surfaces comprising components that reflect afraction of broad spectrum light (e.g., microspheres) in addition tocomponents that selectively absorb or reflect certain colors (e.g.,pigments or dyes) are typically less saturated due to the increase in L*associated with the reflected broad spectrum light. It is typicallydesirable in colored articles to lower the fraction of reflected broadspectrum light so that the true color of the article is observed. Forexample, in articles where there is a stronger front surface reflectiondue to the higher refractive index of the microsphere, the observedcolor of the article could typically appear less saturated (i.e., a“washed out” appearance).

In the present disclosure, the refractive index of the transparentmicrospheres are selected such that they have a refractive index that isless than the refractive index of the binder to enable true color of theunderlying layers. In some embodiments of the present disclosure thedifference is at least 0.15, 0.02 or even 0.03. In some embodiments ofthe present disclosure, this difference in the refractive index is atmost 0.50, 0.20, 0.15, 0.08, or even 0.04.

Substrate Layers

The presently disclosed microsphere coated articles and transferarticles can optionally comprise one or more substrate layer(s).Examples of suitable substrate layers include but are not limited tothose selected from at least one of fabrics (including synthetics,non-synthetics, woven and non-woven such as nylon, polyester, etc.),polymer coated fabrics such as vinyl coated fabrics, polyurethane coatedfabrics, etc.; leather; metal; paint coated metal; paper; polymericfilms or sheets such as polyethylene terephthalate, acrylics,polycarbonate, polyurethane, elastomers including natural and syntheticrubber such as neoprene, and the like. The substrates may, for example,be in the form of a clothing article; automobile, marine, or othervehicle seat coverings; automobile, marine, or other vehicle bodies;orthopedic devices; electronic devices, hand held devices, householdappliances, and the like.

In the presently disclosed transfer and microsphere coated articles, theplurality of transparent microspheres are typically provided as acontinuous layer in some embodiments or in some embodiments as adiscontinuous layer (e.g., patterned). The binder layer is continuous insome embodiments or discontinuous in some embodiments. The substrateadhesive, when present, may be continuous in some embodiments ordiscontinuous in some embodiments. Typically, the substrate layer, whenpresent, is continuous, although it may be discontinuous. In thepresently disclosed microsphere coated articles all layers canoptionally be continuous or discontinuous (e.g., patterned).

Graphic Layer Options

The present disclosed binder layer can optionally also perform thefunction of acting as the adhesive for a desired substrate and/orfurther comprise pigment(s) such that it also has a graphic function.

The binder layer, when selected to function also as a substrateadhesive, may be, for example, pigmented and provided in the form of animage, such as, for example, by screen printing the adhesive in the formof a graphic for transfer to a separate substrate. However, the binderlayer, in some instances, is preferably colorless and transparent sothat it can allow transmission of color from either a substrate,separate graphic layers (discontinuous colored polymeric layers) placedbelow it, or from a separate substrate adhesive that is optionallycolored and optionally printed in the form of a graphic image (adiscontinuous layer).

Typically, if a graphic image is desired it is provided separately onthe surface of the binder layer opposite the plurality of embeddedtransparent microspheres by at least one colored polymeric layer. Theoptional colored polymeric layer may, for example, comprise an ink.Examples of suitable inks for use in the present disclosure include butare not limited to those selected from at least one of pigmented vinylpolymers and vinyl copolymers, acrylic and methacrylic copolymers,urethane polymers and copolymers, copolymers of ethylene with acrylicacid, methacrylic acid and their metallic salts, and blends thereof. Thecolored polymeric layer, which can be an ink, can be printed via a rangeof methods including, but not limited to screen printing, flexographicprinting, offset printing, lithography, transfer electrophotography,transfer foil, and direct or transfer xerography. The colored polymericlayer may be transparent, opaque, or translucent.

If retroreflective performance is desired, the colored polymeric layeror multiple colored polymeric layers should be thin enough to maintainthe contour of the plurality of transparent microspheres. The lastunderlying layer should be a reflecting layer such as a polymeric layercontaining nascent reflecting particles such as aluminum flake or ametallic layer such as vapor deposited aluminum. The resultant graphicimage could be a combination of individual retroreflective andnon-retroreflective images when opaque colored polymeric layers areprinted in some areas and reflecting colored polymeric layers areprinted in other areas. The graphic could encompass a broad range ofcolor, especially if a 4-color graphic process is employed.

A colored polymeric layer(s) may be included in the articles of thepresent disclosure by a number of procedures. For example, a transfercarrier can have a layer of transparent microspheres embedded in therelease layer thereof, following which the microsphere embedded surfaceof the release layer is coated with a transparent layer of binder. Thismicrosphere and adhesive coated transfer carrier can function as acasting liner by coating, for example, a continuous colored plasticizedvinyl layer over the binder layer and wet laminating a woven ornon-woven fabric thereover.

Another method involves providing graphic layers (discontinuous coloredpolymeric layers, for example) on the binder layer prior to casting acontinuous colored plasticized vinyl layer to approximate the image ofleather, for example.

Optional Adhesive Layer(s)

The presently disclosed microsphere coated article and transfer articlemay each optionally further comprise one or more adhesive layers inaddition to the binder layer. A substrate adhesive layer, for example,may optionally be included in the article in order to provide a meansfor bonding the binder layer or the layer(s) of material optionallybonded to the binder layers to a substrate. These optional adhesivelayer(s) may be optionally present when, for example, the binder layercannot function also as an adhesive for a desired substrate. A substrateadhesive layer (as well as any other optional adhesive layers) maycomprise the same general types of polymeric materials used for thebinder layer and may be applied following the same general procedures.However, each adhesive layer used must be selected such that it willadhere the desired layers together. For example, a substrate adhesivelayer must be selected such that it can adhere to an intended substrateas well as to the other layer to which it is bonded.

Reinforcing Layer(s)

Optional layers may be included in the presently disclosed microspherecoated article and transfer article to, for example, enhance the abilityto separate the transfer carrier from the layer of a plurality oftransparent microsphere. Such an optional layer which in such an articlecan function as a reinforcing layer would typically be positioned inbetween the plurality of transparent microspheres and a substrateadhesive layer. Examples of useful reinforcing layers would includeadditional substrate layer(s), for example.

A transparent microsphere coated and adhesive coated transfer carriercould be coated with a fabric adhesive such as a polyester, or apolyamide, followed by lamination to a woven fabric or to a moisturetransmitting membrane, to function as a slippery liner for clothing, forexample.

Embossing

The articles of the present disclosure may optionally be embossed. Theembossing procedure would typically involve subjecting the article,bonded to an embossable substrate, and with the transfer carrierremoved, to heat and pressure such as by a heated patterned rollerassembly or a patterned heated platen press. For embossed articles it ispreferable that the binder layer not be melted during the embossingoperation, to preserve the microsphere embedment level, while at thesame time flexible enough to be deformed without cracking. Anothermethod of embossing would be to thermally laminate the transfer articleto an irregular substrate such as, for example a coarse fabric such thatafter the transfer carrier is removed, that the surface is conformed tothe irregular layer below it. In some embodiments, thermoforming can beused when processing the presently disclosed articles and transferarticles.

Referring now to FIG. 1, there is a cross-section, an embodiment of thepresently disclosed article 10, wherein a plurality of transparentmicrospheres 11 have been operable affixed to one or more layers, suchas for example a substrate layer 13. Article 10 includes a layer of aplurality of transparent microspheres 11 that have beenelectrostatically sprayed on the surface of a binder layer 12 while itwas in a tacky state. In some embodiments, the transparent microspheresare embedded in the binder layer to a level between 30% to 40% of thediameter of the microspheres.

In some embodiments, the plurality of transparent microspheres 11 areselected to have a refractive index that is lower than the refractiveindex of the binder layer 12. In some embodiments, the transparentmicrospheres have a refractive index of less than about 1.490. In someembodiments, the plurality of transparent microspheres 11 have arefractive index of less than about 1.480. In some embodiments, theplurality transparent microspheres 11 have a refractive index of lessthan about 1.470. In some embodiments, the plurality of transparentmicrospheres 11 have a refractive index of less than about 1.46. In someembodiments, the plurality of transparent microspheres 11 have arefractive index of less than about 1.45. In some embodiments, theplurality of transparent microspheres 11 have a refractive index of lessthan about 1.40. In some embodiments, the plurality of transparentmicrospheres 11 have a refractive index of less than about 1.35 or less.

In some embodiments, the binder layer 12 is disposed on a substratelayer 13. In some embodiments, a pressure-sensitive adhesive layer canbe disposed on a side of the substrate layer 13 opposite the side whichis bonded to binder layer 12. In some embodiments, thepressure-sensitive adhesive layer is protected by a removable releaseliner. In some embodiments, article 10 is suitable for lamination toanother substrate (not shown).

FIG. 2 is a cross-section of an embodiment of the presently disclosedtransfer article 20, comprising a transfer carrier comprising temporarysupport layer 23 bonded to thermoplastic release layer 22. A layer of aplurality of transparent microspheres 21 are temporarily embedded inroughly a one-half state in thermoplastic release layer 22. In someembodiments, the transparent microspheres are embedded in thethermoplastic release layer to a level between 30% to 40% of thediameter of the microspheres. Support layer 23 is positioned againstthermoplastic release layer 22. The transfer article 20 may be used byremoving support layer 23 to expose thermoplastic release layer 22.Thermoplastic release layer 22 can then be attached to a substrate (notshown).

A non-limiting list of exemplary embodiments and combinations ofexemplary embodiments of the present disclosure are disclosed below:

Embodiment 1. An article comprising at least a first surface having: (a)a first binder layer; (b) a plurality of transparent microspheres atleast partially embedded in the first binder layer; wherein thetransparent microspheres have refractive indices that are less than arefractive index of the first binder layer, wherein the plurality oftransparent microspheres have an average diameter of at least 5 μm.

Embodiment 2. The article of embodiment 1 wherein the plurality oftransparent microspheres have a refractive index of no more than 1.490.

Embodiment 3. The article of any of the preceding embodiments whereinthe plurality of transparent microspheres are selected from at least oneof glass, polymers, glass ceramics and ceramics.

Embodiment 4. The article of any of the preceding embodiments whereinthe first binder layer is selected from at least one of polyurethanes,polyesters, acrylic and methacrylic acid ester polymers and copolymers,epoxies, polyvinyl chloride polymers and copolymers, polyvinyl acetatepolymers and copolymers, polyamide polymers and copolymers, fluorinecontaining polymers and copolymers, silicones, silicone containingcopolymers, elastomers, such as neoprene, acrylonitrile butadienecopolymers, metals, glass, ceramics, polymer matrix composites, andcombinations thereof.

Embodiment 5. The article of any of the preceding embodiments where inthe first binder layer is an adhesive.

Embodiment 6. The article of any of the preceding embodiments whereinthe plurality of transparent microspheres have an average diameter of nogreater than 200 μm.

Embodiment 7. The article of any of the preceding embodiments wherein upto about 91% of the surface of the article is covered with the pluralityof transparent microspheres.

Embodiment 8. The article of any of the preceding embodiments wherein atleast one of the article or the binder layer comprises a pigment.

Embodiment 9. The article of any of the preceding embodiments whereinthe plurality of transparent microspheres are partially embedded in thefirst binder layer such that about 20% to about 70% of the averagediameter of the transparent microspheres is exposed.

Embodiment 10. The article of any of the preceding embodiments whereinthe plurality of transparent microspheres have a multi-modal sizedistribution.

Embodiment 11. The article of any of the preceding embodiments whereinthe article is at least one of a decorative film, a protective film, atransfer article.

Embodiment 12. The article of any of the preceding embodiments whichfurther comprises one or more layers selected from the group consistingof substrate layers, adhesive layers, colored polymeric layers, andrelease layers bonded to the article on a side of the first binder layeropposite the plurality of transparent microspheres, wherein any of saidlayers can optionally have a graphic design therein.

Embodiment 13. The article of embodiment 12 wherein the substrate layerfrom at least one of fabrics, polymer coated fabrics, leather, metal,paint coated metal, elastomers, paper, polymer matrix composites, andpolymeric materials.

Embodiment 14. The article of any of the preceding embodiments whereinthe transparent microspheres are treated with an adhesion promoter.

Embodiment 15. The article of any of the preceding embodiments whereinthe first binder layer is transparent.

Embodiment 16. A transfer article comprising: (a) a transfer carrier,the transfer carrier comprising: (i) a support layer; and (ii) athermoplastic release layer bonded to the support layer; (b) a layer ofa plurality of transparent microspheres, formed on a side of thethermoplastic transparent microsphere release layer opposite the supportlayer, wherein the plurality of transparent microspheres have refractiveindices of no more than 1.490.

Embodiment 17. The transfer article of embodiment 16 further comprising(c) a binder layer on a side of the plurality of transparentmicrospheres that is opposite the thermoplastic release layer.

Embodiment 18. The transfer article of any of embodiments 16 to 17wherein the plurality of transparent microspheres are selected from atleast one of glass, polymers, glass ceramics and ceramics.

Embodiment 19. The transfer article of any of embodiments 17 to 18wherein the first binder layer is selected from at least one ofpolyurethanes, polyesters, acrylic and methacrylic acid ester polymersand copolymers, epoxies, polyvinyl chloride polymers and copolymers,polyvinyl acetate polymers and copolymers, polyamide polymers andcopolymers, fluorine containing polymers and copolymers, silicones,silicone containing copolymers, elastomers, such as neoprene,acrylonitrile butadiene copolymers, metals, glass, ceramics, polymermatrix composites, and combinations thereof.

Embodiment 20. The transfer article of any of embodiments 17 to 19 wherein the first binder layer is an adhesive.

Embodiment 21. The transfer article of any of embodiments 16 to 20wherein the plurality of transparent microspheres have an averagediameter of no greater than 200 μm.

Embodiment 22. The transfer article of any of embodiments 16 to 21wherein up to about 91% of the surface of the article is covered withthe plurality of transparent microspheres.

Embodiment 23. The transfer article of any of embodiments 17 to 22wherein at least one of the transfer article or the binder layercomprises a pigment.

Embodiment 24. The transfer article of any of embodiments 17 to23wherein the plurality of transparent microspheres are partially embeddedin the first binder layer such that about 20% to about 70% of theaverage diameter of the transparent microspheres is exposed.

Embodiment 25. The transfer article of any of embodiments 16 to 24wherein the plurality of transparent microspheres has a multi-modal sizedistribution.

Embodiment 26. The transfer article of any of embodiments 16 to 25further comprising at least one layer selected from at least one ofsubstrate layers, adhesive layers, colored polymeric layers, and releaselayers bonded to the article on a side of the first binder layeropposite the plurality of transparent microspheres, wherein any of saidlayers can optionally have a graphic design therein.

Embodiment 27. The transfer article of embodiment 26 wherein thesubstrate layer from at least one of fabrics, polymer coated fabrics,leather, metal, paint coated metal, elastomers, paper, polymer matrixcomposites, and polymeric materials.

Embodiment 28. The transfer article of any embodiments 16 to 27 whereinthe transparent microspheres are treated with an adhesion promoter.

Embodiment 29. The transfer article of any of embodiments 17 to 28wherein the first binder layer is discontinuous (e.g., a pattern) andwherein the binder layer is capable of bonding to a substrate layer.

Embodiment 30. The transfer article of any of embodiments 16-29 whereintransparent microspheres in the plurality of transparent microspherescomprise at least 5% by weight of boron oxide.

Embodiment 31. The transfer article of any of embodiments 16-30 whereinthe difference between the refractive index of a binder in the firstbinder layer and the refractive index of the transparent microspheres isat least 0.015.

Embodiment 32. The article of any of embodiments 1-15 whereintransparent microspheres in the plurality of transparent microspherescomprise at least 5% by weight of boron oxide.

Embodiment 33. The article of any of embodiments 1-15 or embodiment 32wherein the difference between the refractive index of a binder in thefirst binder layer and the refractive index of the transparentmicrospheres is at least 0.015.

Embodiment 34. The article of any of embodiments 1-15 or embodiments32-33, wherein the article further comprises a second layer opposite thefirst surface comprising the plurality of transparent microspheres atleast partially embedded in the first binder layer, wherein the secondlayer is colored.

Various modifications and alterations of this invention will becomeapparent to those skilled in the art without departing from the scopeand spirit of this invention.

EXAMPLES Materials

Designation Description K-FLEX 188 100% active polyester polyol obtainedfrom King Industries, Inc., Nowalk, CT DESMODUR N3300A solvent freepolyfunctional aliphatic isocyanate resin based onhexamethylenediisocyanate, obtained from Bayer Materials Science,Pittsburgh, PA K-KAT XC-9213 zirconium chelate complex obtained fromKing Industries, Inc., Nowalk, CT EPON 828 Diglycidyl ether of bisphenolA, obtained from Momentive Specialty Chemicals, Houston, TX JEFFAMINED-230 A difunctional, primary amine with an average molecular weight of230, obtained from Huntsman Corporation, The Woodlands, TX

Method for Making the Transfer Articles

To make the transfer article, a polyethylene coated paper substrate washeated to a temperature of about 140° C. to soften and make its surfacetacky. Transparent microspheres were sprinkled over the polyethylenecoated side of the heated polyethylene coated paper substrate forming amonolayer coating of transparent microspheres (on the polyethylenecoated side of the substrate). The transparent microspheres werepartially embedded in the polyethylene coating side of the polyethylenecoated paper substrate to a depth equivalent of about 30-40% of theirdiameter. The degree to which the transparent microspheres were embeddedin the polyethylene could be controlled by varying the temperature andthe heating time of the polyethylene coated paper substrate.

Method I for Making the Microsphere Articles

A polyurethane binder composition was prepared by mixing 11 grams ofK-FLEX 188, to which 5 wt. % of a carbon black pigment (obtained fromPennColor, Inc., Doylestown, Pa.) was added, and 10 grams of DESMODUR N3300A to which 1 drop of K-KAT XC-9213 was added.

The resulting polyurethane mixture was then coated on the above transferarticle over the transparent microspheres, (thickness of thepolyurethane coating was about 125 μm) and allowed to cure at 70° C. for1 hour. Samples were removed from the oven and the liner comprising thepolyethylene coated paper substrate was peeled off to form and exposethe microsphere article.

Method II for Making the Microsphere Articles

A epoxy binder composition was prepared by mixing 10 grams of EPON 828resin and 5.2 grams of JEFFAMINE D-230 curative. The resulting mixturewas coated on the above transfer article over the transparentmicrospheres, (thickness of the epoxy coating was 150 microns) andallowed to cure at 85° C. for 1 hour. Samples were removed from the ovenand the liner comprising the polyethylene coated paper substrate waspeeled off to form and expose the microsphere article. Final cure wasthen achieved by exposing the microsphere article to 120° C. for 2hours.

The microsphere articles were spray painted on the surface opposite theembedded mircorspheres using a black paint available under the tradedesignation “RUST-OLEUM FLAT SPRAY PAINT” (Rust-Oleum Corp., VernonHills, Ill.).

Refractive Index Measurement (Becke Line Method)

A set of certified refractive index test liquids available from Cargilleof Cedar Grove, N.J. were used to determine the refractive index of thetransparent microspheres using the procedure described below.

A sample of the transparent microspheres were placed on a microscopeslide and a drop of test liquid is contacted with the sample and coveredwith a cover slip. The microscope was adjusted to focus on the beads. Atfocus, the stage of the microscope is lowered using the focus and thebright line at the outline of the microsphere is observed as the focuswas changed. If the bright line travels outward into the liquid as thestage is lowered, then the liquid had a higher index of refraction thanthe bead. If, on the other hand, the bright line travels into the bead,then the microsphere had the higher index of refraction. By testing aseries of liquids of different index the approximate index of themicrosphere was identified. If two liquids lie on either side of theindex of refraction of the microsphere then an interpolation of the truenumber was made.

Refractive Index of Polyurethane Binder Composition Used in Method I

A polyurethane binder composition was prepared as described in theMethod I for Making the Microsphere Articles (above) except that thecarbon black pigment was not added. The resulting polyurethane mixturewas coated onto a release liner and cured at 70° C. for 1 hour. Therelease liner was removed and the resulting film was tested for itsrefractive index using the Becke Line Method (above). The resultingpolyurethane film had a refractive index of 1.502.

Refractive Index of Epoxy Binder Composition Used in Method II

The calculated refractive index of the resulting epoxy film used inMethod II was determined using known refractive indices of the startingmaterials. The refractive index was calculated to be 1.542.

Method of Measuring Color and Luminosity

Color and luminosity (CIE L*, a*,b* values) of the microsphere articlesprepared as described above were determined using a spectrophotometer(such as one commercially available under the trade designation“HunterLab MiniEZ”, obtained from Hunter Associates Labs Inc., RestonVa.) under conditions of 45/0 directional illumination. Samples werealso examined visually (by naked eye) and perceived color was noted.

Example 1 (EX1)

EX1 microsphere article and the transfer article were prepared using theMethod I for Making the Microsphere Articles described above. Thetransparent microspheres were borosilicate glass microspheres with anaverage size of 44-53 μm (obtained from Mo Sci, Inc., Rolla, Mo.) with arefractive index of 1.46 as determined by the Becke Line method. Thetransparent microspheres were sprinkled over a polyethylene coated papersubstrate and heated to about 140° C., to form a monolayer oftransparent microspheres wherein the microspheres were embedded into thepolyethylene layer about 30-40% of their diameter. After the blackpigmented polyurethane coating (125 μm thick) was applied over themicrosphere coated paper and cured by placing in an oven at 70° C. for 1hour, the liner comprising the polyethylene coated paper substrate wasremoved to form a free standing black film containing partially exposedmicrospheres.

Color and luminosity (CIE L*, a*, b* values) of the EX1 microspherearticle was determined as described above.

Comparative Example 1 (CE1)

CE1 microsphere article and transfer articles were prepared in the samemanner as EX1, except that the transparent microspheres weresoda-lime-silicate microspheres with an average size of about 44-53 μm(obtained from Swarco Industries, Inc., Columbia, Tenn.). The refractiveindex of the transparent microspheres was measured to be 1.52 using theBecke Line method.

Color and luminosity (CIE L*, a*, b* values) of the CE1 microspherearticle was determined as described above.

Example 2 (EX2)

EX2 microsphere article and the transfer article were prepared using theMethod I for Making the Microsphere Articles described above.

The transparent microspheres were borosilicate glass microspheres withan average size of less than 63 μm and with a refractive index of 1.458as determined using the Becke Line Method. The above transparentborosilicate glass microspheres were prepared by spherodizing recycledborosilicate glass feed particles (obtained from Strategic Materials,Houston Tex.), through a H₂/O₂ flame at a rate of approximately 3 gramsper minute. The resulting spherodized particles were collected in asteel container, metallic impurities were removed using a magnet andprocessed through the H₂/O₂ flame for a second time to improve theirpurity and homogeneity.

The transparent microspheres were sprinkled over a polyethylene coatedpaper substrate heated to about 140° C., to form a monolayer oftransparent microspheres wherein the microspheres were embedded into thepolyethylene layer about 30-40% of their diameter. After the blackpigmented polyurethane coating (125 μm thick) was applied over themicrosphere coated transfer article and cured by placing in an oven at70° C. for 1 hour, the liner comprising the polyethylene coated papersubstrate was stripped to form a free standing black film containingpartially exposed microspheres.

Color and luminosity (CIE L*, a*,b* values) of the EX2 microspherearticle was determined as described above.

Comparative Example 2 (CE2)

CE2 microsphere article and transfer articles were prepared in the samemanner as EX2, above except that the transparent microspheres werecalcium aluminosilicate microspheres with an average size of about 30-75μm and a refractive index of 1.61 as determined using the Becke Linemethod. The transparent calcium aluminosilicate microspheres wereprepared by feeding calcium aluminosilicate granules through a H₂/O₂flame at a rate of approximately 3 grams per minute. The resultingspherodized particles were collected in a steel container and processedthrough the H₂/O₂ flame for a second time to improve their homogeneity.

The transparent microspheres were sprinkled over a polyethylene coatedpaper substrate and heated to about 140° C., to form a monolayer oftransparent microspheres wherein the microspheres were embedded into thepolyethylene layer about 30-40% of their diameter. After the blackpigmented polyurethane coating (125 μm thick) was applied over themicrosphere-coated paper substrate and cured by placing in an oven at70° C. for 1 hour, the liner comprising the polyethylene coated papersubstrate was removed to form a free standing black film containingpartially exposed microspheres.

Color and luminosity (CIE L*, a*,b* values) of the CE2 microspherearticle was determined as described above.

Comparative Example 3 (CE3)

A coating of black pigmented polyurethane binder composition describedabove was applied over a microreplicated dimpled polyethylene surface(dimple size ˜30 μm) and cured in an oven at 70° C. for 1 hour. Theblack pigmented polyurethane coating was about 125 μm thick. Thepolyethylene carrier was then stripped to reveal a low gloss black film.

The Table 1, below summarizes the properties of Example 1, 2 andComparative Examples 1-3. Note that the refractive index mismatch is thedifference between the refractive indices of the microsphere and thebinder for corresponding sample.

TABLE 1 Refractive Index Perceived Color Sample Binder MicrosphereDifference Pigment Color L* a* b* EX1 1.502 1.460 0.042 black black-12.59 −0.18 −1.08 gray EX2 1.502 1.458 0.043 black black 10.86 0.06−0.18 CE1 1.502 1.520 −0.018 black dark gray 15.21 −0.02 −0.05 CE2 1.5021.650 −0.148 black dark gray 15.41 −0.01 −0.36 CE3 1.502 1.502 0 blackdark gray 15.545 0.07 −0.05

Example 3 (EX3)

EX3 was prepared using Method II for Making the Microsphere Articlesdescribed above.

The transparent microspheres were borosilicate glass microspheres withan average size of less than 63 μm and with a refractive index of 1.458as determined using the Becke Line Method. The above transparentborosilicate glass microspheres were prepared by spherodizing recycledType 1 borosilicate glass feed particles (obtained from StrategicMaterials, Houston Tex.), through a H₂/O₂ flame at a rate ofapproximately 3 grams per minute. The resulting spherodized particleswere collected in a steel container, metallic impurities were removedusing a magnet and processed through the H₂/O₂ flame for a second timeto improve their purity and homogeneity.

The transparent microspheres were sprinkled over a polyethylene coatedpaper substrate heated to about 140° C., to form a monolayer oftransparent microspheres wherein the microspheres were embedded into thepolyethylene layer about 30-40% of their diameter. After the epoxycoating (150 μm thick) was applied over the microsphere embeddedpolyethylene coated paper substrate, the substrate was cured in an ovenat 85° C. for 1 hour. Afterwards, the liner comprising the polyethylenecoated paper substrate was removed to form a free standing clear filmcontaining partially exposed microspheres. Final cure was achieved byexposing the microsphere article to 120° C. for 2 hours. The back sideof the microsphere article was then spray painted black as describedabove.

Color and luminosity (CIE L*, a*,b* values) of the EX3 microspherearticle was determined as described above.

Example 4 (EX4)

EX4 was prepared using Method II for Making the Microsphere Articlesdescribed above.

The transparent microspheres were ‘51 expansion borosilicate’ glassmicrospheres with an average size of less than 63 μm and with arefractive index of 1.470 as determined using the Becke Line Method. Thetransparent borosilicate glass microspheres were prepared byspherodizing milled borosilicate glass feed particles (prepared by discmilling ‘51 expansion borosilicate’ glass tubing obtained fromGerresheimer, Vineland, N.J.), through a H₂/O₂ flame at a rate ofapproximately 3 grams per minute. The resulting spherodized particleswere collected in a steel container.

The transparent microspheres were sprinkled over a polyethylene coatedpaper substrate and heated to about 140° C., to form a monolayer oftransparent microspheres wherein the microspheres were embedded into thepolyethylene layer about 30-40% of their diameter. After the epoxycoating (150 μm thick) was applied over the microsphere coated transferarticle and cured by placing in an oven at 85° C. for 1 hour, the linercomprising the polyethylene coated paper substrate was removed to form afree standing clear film containing partially exposed microspheres.Final cure was achieved by exposing the microsphere article to 120° C.for 2 hours. The back side of the microsphere article was then spraypainted black as described above.

Color and luminosity (CIE L*, a*,b* values) of the EX3 microspherearticle was determined as described above.

Comparative Example 4 (CE4)

CE4 microsphere article and transfer articles were prepared in the samemanner as EX4, except that the transparent microspheres weresoda-lime-silicate microspheres with an average size of about 44-53 μm(obtained from Swarco Industries, Inc., Columbia, Tenn.). The refractiveindex of the transparent microspheres was measured to be 1.520 using theBecke Line method.

Color and luminosity (CIE L*, a*, b* values) of the CE1 microspherearticle was determined as described above.

Comparative Example 5 (CE5)

CE5 microsphere article and transfer articles were prepared in the samemanner as EX4, except that the transparent microspheres wereborosilicate E-glass microspheres with a particle size in the range of20-75 μm (obtained from Potter's Industries, Malvern, Pa.). Themicrospheres were passed through a H2/O2 flame to improve their defectlevels. The refractive index of the transparent microspheres wasmeasured to be 1.57 using the Becke Line Method.

Color and luminosity (CIE L*, a*, b* values) of the CE1 microspherearticle was determined as described above.

TABLE 2 Refractive Index Sam- Micro- Differ- Paint Color ple Bindersphere ence applied L* a* b* EX3 1.542 1.458 0.083 black 18.67 0 −0.28EX4 1.542 1.470 0.072 black 18.21 −0.08 −0.26 CE4 1.542 1.520 0.022black 21.28 −0.05 −0.21 CE5 1.542 1.570 −0.028 black 21.56 −0.09 −0.12

1. An article comprising at least a first surface having: (a) a firstbinder layer; (b) a plurality of transparent microspheres at leastpartially embedded in the first binder layer; wherein the transparentmicrospheres have refractive indices that are less than a refractiveindex of the first binder layer, wherein the plurality of transparentmicrospheres have an average diameter of at least 5 μm.
 2. The articleof claim 1 wherein the plurality of transparent microspheres have arefractive index of less than 1.49.
 3. The article of claim 1 whereinthe plurality of transparent microspheres are selected from at least oneof glass, polymers, glass ceramics and ceramics.
 4. The article of claim1 wherein the first binder layer is selected from at least one ofpolyurethanes, polyesters, acrylic and methacrylic acid ester polymersand copolymers, epoxies, polyvinyl chloride polymers and copolymers,polyvinyl acetate polymers and copolymers, polyamide polymers andcopolymers, fluorine containing polymers and copolymers, silicones,silicone containing copolymers, elastomers, such as neoprene,acrylonitrile butadiene copolymers, metals, glass, ceramics, polymermatrix composites, and combinations thereof.
 5. The article of claim 1where in the first binder layer is an adhesive.
 6. The article of claim1 wherein the plurality of transparent microspheres have an averagediameter of no greater than 200 μm.
 7. The article of claim 1 wherein upto about 91% of the surface of the article is covered with the pluralityof transparent microspheres.
 8. The article of claim 1 wherein at leastone of the article or the binder layer comprises a pigment.
 9. Thearticle of claim 1 wherein the plurality of transparent microspheres arepartially embedded in the first binder layer such that about 20% toabout 70% of the average diameter of the transparent microspheres isexposed.
 10. The article of claim 1 wherein the plurality of transparentmicrospheres have a multi-modal size distribution.
 11. The article ofclaim 1 wherein the article is at least one of a decorative film, aprotective film, a transfer article.
 12. The article of claim 1 whichfurther comprises one or more layers selected from the group consistingof substrate layers, adhesive layers, colored polymeric layers, andrelease layers bonded to the article on a side of the first binder layeropposite the plurality of transparent microspheres, wherein any of saidlayers can optionally have a graphic design therein.
 13. The article ofclaim 12 wherein the substrate layer from at least one of fabrics,polymer coated fabrics, leather, metal, paint coated metal, elastomers,paper, polymer matrix composites, and polymeric materials.
 14. Thearticle of claim 1 wherein the transparent microspheres are treated withan adhesion promoter.
 15. The article of claim 1 wherein the firstbinder layer is transparent.
 16. A transfer article comprising: (a) atransfer carrier, the transfer carrier comprising: (i) a support layer;and (ii) a thermoplastic release layer bonded to the support layer; (b)a layer of a plurality of transparent microspheres, formed on a side ofthe thermoplastic transparent microsphere release layer opposite thesupport layer, wherein the plurality of transparent microspheres haverefractive indices of below about 1.49.
 17. The transfer article ofclaim 16 further comprising (c) a binder layer on a side of theplurality of transparent microspheres that is opposite the thermoplasticrelease layer. 18.-19. (canceled)
 20. The transfer article of claim 17where in the first binder layer is an adhesive.
 21. (canceled)
 22. Thetransfer article of claim 16 wherein up to about 91% of the surface ofthe article is covered with the plurality of transparent microspheres.23. (canceled)
 24. The transfer article of claim 17 wherein theplurality of transparent microspheres are partially embedded in thefirst binder layer such that about 20% to about 70% of the averagediameter of the transparent microspheres is exposed. 25.-29. (canceled)